Chat is now a module of its own. You create a widget, set its colour, picture and wording, paste one line of code onto your own website, and from that moment you can talk to the people walking around on it.
A visitor who starts typing becomes a conversation in the shared inbox, next to email and form submissions, on the timeline of the same contact. You reply from that same screen. Both sides see messages arrive without refreshing the page.
You set opening hours, and outside them the visitor gets a message rather than a window nobody is reading. If they leave their details, they can reopen the conversation later.